title: Lipomatous tumors of the oral mucosa: histomorphological, histochemical and immunohistochemical features.
abstract: We conducted a comprehensive study of all lipomatous tumors of the oral mucosa (1996-2008) accessioned at the Department of Oral Pathology, Tel Aviv University, collected demographic data and analyzed multiple histomorphological features. Furthermore, we examined the immunostaining of aP2 (adipocyte lipid binding protein) and the polarization colors of picrosirius red (PSR)-stained collagen fibers in order to test their potential in differentiating between benign and malignant tumors. All cases were immunohistochemically stained with aP2 antibody; only tumors with considerable collagenous stroma were selected for the PSR staining. A total of 77 tumors were included in the study, 91% benign and 9% malignant. Fibrolipoma (37.7%) and lipoma (36.4%) were the most frequent tumors. Atypical lipomatous tumor (ALT) was the only type of malignancy. The most common location for the benign tumors was the buccal mucosa and for ALT, the tongue. Histomorphological features characteristic of malignant tumors were occasionally present also in the benign entities. Expression of aP2 was similar in all tumors, while the polarization colors of the PSR-stained collagen fibers differed significantly between ALT and benign tumors (p<0.05). Benign and malignant tumors occasionally show overlapping histomorphological features that require a meticulous examination. PSR staining with polarization microscopy could aid in differentiating malignant from benign tumors in equivocal cases.
authors.affiliation: Department of Oral Pathology and Oral Medicine, School of Dental Medicine, Tel-Aviv University, Tel Aviv, Israel.
authors.forename: Irit
authors.initials: I
authors.lastname: Allon
authors.forename: Sara
authors.initials: S
authors.lastname: Aballo
authors.forename: Dan
authors.initials: D
authors.lastname: Dayan
authors.forename: Marilena
authors.initials: M
authors.lastname: Vered
mesh_terms: D001391:Azo Compounds; D014408:Biomarkers, Tumor; D050556:Fatty Acid-Binding Proteins / Q000032:analysis / Q000378:metabolism*; D006651:Histocytochemistry; D006801:Humans; D007150:Immunohistochemistry; D008067:Lipoma / Q000378:metabolism / Q000473:pathology; D009061:Mouth Mucosa / Q000473:pathology; D009062:Mouth Neoplasms / Q000378:metabolism / Q000473:pathology; D018205:Neoplasms, Adipose Tissue / Q000378:metabolism / Q000473:pathology; D013194:Staining and Labeling
chemical_list: D001391:Azo Compounds; D014408:Biomarkers, Tumor; C493410:FABP4 protein, human; D050556:Fatty Acid-Binding Proteins; C009798:C.I. direct red 80